Magnetic switch



April 1933- w. F. HURLBURT 1,904,141

MAGNETIC SWITCH Filed June 27, 1929 2 Sheets-Sheet l [MEZiEVCY [0A0 PREDOM/A/A rws L/NE INVENTORV Wilbur E Harlbwrt 62 0am, @W QM ATTORNEYS Patented Apr. 18, 1933 UNITED STATES PATENT OFFICE a WILBUR F. HURLBURT, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO AUTOMATIC SWITCH COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK MAGNETIC SWITCH Application filed June 27,

This invention relates to electric switches which are magnetically controlled and more particularly to switches in which the operating magnet is excited only during the period of closing or of opening the switch.

It is one of the objects of the invention to provide a switch of the foregoing character which shall be simple and compact and which shall comprise a unitary magnetic operating unit and also a unitary switch structure, the latter being ether single pole or multiple pole and either single or double throw, the magnetic operating unit and the switch unit each being constructed to be readily interchangeable with other units.

A further object of the invention is to provide a spring pressed electrical contact and positive connections for moving said spring pressed contact into and out of electrical contact by the magnetic operating unit in such a manner that the force is automatically increased as the contact is moved further in against the increasing action of the spring and so that the effective tendency of A the spring contact to move out of contact is minimized- This arrangement also insures positive operation of the switch although there may be only a momentary energization of the operating magnet.

These and other objects of the invention will appear to those skilled in the art to which it appertains by a consideration of the following description of one embodiment of the invention taken in connection with the accompanying drawings in which Fig. 1 is a front elevation of a three-pole double-throw magnetic switch, certain of the electrical connections being shown in diagrammatic form;

Fig. 2 is an end elevation of the operating magnet of Fig. 1

Fig. 3 is a vertical section taken on the line 3-3 of Fig. 1;

Fig. 4 is a vertical section taken on the line 4-4 of Fig. 1; and

Fig. 5 is a section similar to Fig. 4 with the operating parts in a different position.

Referring to the drawings more in detail the reference character 11 indicates a supporting panel preferably of insulating material 1929. Serial No. 374,044.

such as slate upon which are mounted bearmg brackets 12 and 13 in which is mounted for oscillatory movement a shaft 14 having its axis horizontal and parallel to the plane of the panel. While this shaft is circular in cross section where it passes through the bearings it is preferably square throughout its in termediate portion as indicated at 15 in order that the contact arms may be securely held thereon and prevented from rotating with re spect to the shaft. Upper contact arms 16, 17 and 18 are secured to the shaft 14 and lower contact arms 19, 20 and 21 are also secured. thereto, there being insulating material 22 interposed between the shaft 14 and the contact arms. Each arm carries a pair of spring pressed contact fingers 23 adapted to make contact with the contact members 24, 25 and 26 respectively when the upper contacts are closed and" with the contact members 27, 28 and 29 respectively when the lower contacts are closed.

The upper contact members 24, 25 and 26 may be connected to an emergency line as indicated diagrammatically by conductors 30, 31 and 32. In a similar manner the lower contact members 27, 28 and 29 may be connected as indicated diagrammatically by conductors 33, 34 and 35 to a predominating line. The predominating line is one which normally predominates over the emergency line and maintains connections between such predominating line and the load but when the predominating line is cut off or fails for any reason the emergency line is automatically connected to the loa i Corresponding oppositecontact arms have their contact fingers 23 connected by means of flexible cables 36 to central terminal blocks 37, there being a separate block for each of the three poles of the switch. These terminal blocks 37 are connected by means of conductors, shown diagrammatically at 38, 39 and 40, to some suitable load as indicated at 41. As will be clearly seen from Fig. 3 the oscillation of the shaft 14 and the contact arms therewith serves to make contact on the lower contact members and to break contact with the upper contact members when the shaft is oscillated to one extreme position and nected with a magnetic operating unit tobe presently described.

lThelmagnetic operating unit has a base or support 43mounted on the panel" 11 and the switch supplied by the line conductor 33 this base carries a solenoid 44 within which is positioned for vertical movement a core 45. The upper portion 46v of the.coreHmaybe smaller than the main portion of the core andpasses through anaperture, of correspondingdiameterin ithe. support 43. The ,upperportion 460i the core is shown thread- .ed andis ,provided with nuts 47'- for adjustablyili niting-the downward movement of the core 45. The lower portion of the supporti.43, e ;te1 1ds beneath the core to -pro- .yide bearings for. a; horizontal shaft 48 disposediparallel vto the plane ofthe panel 11. A momentum memberi49, contact disks 50 and .51, and 13,11, eccentric 52 may be secured ,to. the.-shaft, 48, to oscillate therewith orthey may be secured-together.so .as to oscillate tg'gether upon the shaft .48 while: the latter r' ejrnains stationary. A. connecting link or pitmanfiihas one endpivoted at 54 to the .lowen-end-otthe core 45, and, the other-end oi the pitman ispivotedat55 to the momentum member :49. A springpressed contact fingen56..adap1 cd;to make contact with the periphery ,ofrthe.;diskw50,.is mountedon a 7 member 58 of insulating material and a similar spring pressed contact finger. .57 is. also mountedon the member 58;and isadaptedto make contact (with, the periphery of the, disk 51. jThecontact. disksarev so formed that the fingers do notmake contact therewith at all times. The contact finger u56 does not make contact-withthe disk :50 in the extreme position ofytheshaft 48 shownain 1 .while the ,contact finger 57 does make contact with the di spk.51 in this :position. ;Figs. 2 and 4 showrsimilarposition. ,InFig. .5 the contact finger 5,6 is shown asmaking contact .Withthc disk 50 while the contact finger57 does not make contact with the disk 51. The conformaticn given ;to the contact disks 50 and 51 is preferably suehthat contactis made in each frespectiveposition while the mo- -mentummcmber49 is swingingffromits extreme position. to nearly the dead centerrposition'but the contact; is preferably broken before the momentum nnember reaches the adicc te p itionj orthe operation of the embodiment of the ,invention shown in the drawings there isalso preferably provided a relay having a .coil .59 and an armature ,60 with two contacts 61 and62co7operating with stationary c0nt acts63 and ,64resp-ectively. NVhen the coil 59 is excited the armature 60 is pulled up into the position shown in Fig. 1 and connection is made between the contacts 61 and 63. When the coil is de-energized the armature drops into the lower position breaking' contact, at 6163- and making connectionbetween the contacts62 and 64..

The electrical connections for the magnetic operating unit and the relay are as follows. One terminal of thecoil 59 isconnected by means of acondu-ctor'65'to theterminal of and the other terminal of the coil 59 is connected by,means of a conductor 66 to the terminal of the switch supplied by the line con- 1du'ctor64. iThe armature 60 of the relay is connected bytr means-of a flexible cable 67 and; a;conductor- 68 to'thei-terminal 0f: the

switchwhich is suppliedby thelinecondue- I tor 32. The stationary contact 63 is connectedby' a conduc'tor69 to the contact finger 56 while the stationary contact: 64 is connected by means of a conductor 70 to the contact finger =57. One terminal 71 of the solenoid accomplished. The other terminal73 of the solenoid .44 is connected by. .means of a conductor74 to the terminalof the switch which is Supplied by the lineconductor 30.

' zThe switch shown .inthe drawingsis particularly adapted for usein hospitals,theatres and similar places where there is a circuit for supplying electricity under normalco'nd-itionsand. also :anemergency circuit from a storage battery or other suitable source which emergency line is antomatlcally connected-to the loadiin case of failure of the .usual supply forany reason whatever. The complete arrangement for such a purpose will be described .in connection with the operation of the switch in order that one ultimate purposeof the switch maybe understood in connection .with'the structural de-' tails thereof. I

Fig. 1 shows thepartsin the position they .assumewhen the current is being supplied by thepredominatinglineby means of the conductors 33, 34 and'85. Asmall amount of current is supplied through the conductors 651and- 66 to excite the coil'59 and the armature 60 is thereby held in itsupperposition sothat connection is madebetween the'contacts 61 and 63. The circuit through the conductor 68 is broken through both branches,

through the conductor 70 at the contacts 62 and 64 and through the conductor 69 at the contact finger 56and the disk 50. If for any reason the current through the predominating line fails the armature 60 will be released, connection will be made betweenthe contacts 62 and 64 and the current will pass through conductor 70, contact finger 57, disk 51, conductor 7 2, solenoid 44 and back to the line 30. The core 45 will be drawn upward and through the pitman 53 will draw the momentum member 49 toward the middle position. Just before the parts reach this middle position contact is broken at the disk 51. The momentum of the momentum member 49 will carry it beyond dead center and as it passes downward into the opposite extreme position the weight of the core 45 also pushes the member 49 downward. This movement is indicated in Fig. 2, the initial position being as shown in full lines and the final posi tion being as shown in dot and dash lines. The initial position is also as indicated in Fig. 4 while the final position is as shown in Fig. 5. Figs. 4 and show the manner in which the eccentric 52 moves the forked end of the lever 42 and swings the shaft 14 from one extreme position to the other and breaks the lower contacts as seen in Fig. 3 and at the same time makes connections at the upper contacts.

It will be noticed that the member 49 moves about sixty degrees each side of the vertical axis and as it moves farther from the vertical position the effective lever arm through which the member 49 can push backward and raise the core 45 becomes less and less. And stated conversely the torque exerted by the weight of the core 45 on the member 49 becomes greater the farther the member 49 is away from the middle position. In a similar manner the eccentric 52 acts upon the forked lever 42 with an increasing ratio of leverages the farther the eccentric is moved from the middle position. This increasing leverage is particularly effective in its operation upon the spring pressed contact fingers 23 for two reasons. In the first place the force. with which the springs of the fingers push back is greater the farther the conv tact arms move inwardly and the increasing force of the actuating weight 45 because of the increased leverage likewise increases to take care of the increasing force of the spring. Also the increased leverages in the extreme positions are so marked that it is almost impossible for a force exerted at the end of the switch arms to push back through the linkages and raise the weight of the core 453. This is a desirable feature in the type of construction shown wherein the magnet is not excited after the switch has operated but the holding force is due exclusively to the weight of the core and not upon the strength of the solenoid.

Upon the restoration of the electrical sup ply to the lines 33, 34 and 35 the coil 59 is excited, the armature 60 is raised, contact at 61 and 63 made, and since the contact finger 56 is now making contact with the disk 50 the circuit is completed through the solenoid 44 and the momentum member 49 is carried back to its original extreme position. This movement operates through the linkage to open the upper contacts and closes the lower contacts of the main switch. One of the advantages of the invention is due to the particular arrangement whereby the unitary magnetic device is detachably associated with a unitary switch structure. A few magnetic operating units may be carried in stock and readily assembled with a variety of different switches. The disposition of the shaft 14 and the shaft 48 parallel to the plane of the panel also contributes to the unitary feature and to the use of a plurality of switch arms and contacts.

While in the foregoing the invention has been described particularly in connection with a transfer switch for automatically changing a load from one source of supply to another, it is to be understood that the invention and its structural features are also adapted for use in any suitable place and more especially where a remote control switch or contactor is required. Such switches are usually single throw, and with the construction of the present invention would be controlled by a manually operated, normally open, momentary contact push button switch or equivalent. 1

I claim:

In a magnetic switch, a vertically disposed supporting panel, a contacting member oscillatable about a horizontal axis parallel to said panel, a momentum member also oscillatable about a horizontal axis parallel to said first named axis from one extreme position to another, a solenoid magnet having a vertically moving core adapted when the magnet is excited to move said momentum member from either extreme position toward an intermediate neutral position, means including contact discs rotatable with said momentum member for deenergizing said magnet as the momentum member travels from either extreme position toward the intermediate posltion, said momentum member having a relatively large mass to carry it to the other extreme position, driving connections between sa1d momentum member and treme positions of said momentum member. 1

WILBUR F. HURLBURT. 

